My SES light went off with:

P0172 System too Rich (Bank 1)
P0300 Random/Multiple Cylinder Misfire Detected
P0700 Transmission Control System Malfunction
P1192 Post-catalyst Fuel Trim System Bank 1

My 96 Blazer has almost 200K miles on it. It starts fine & idles rough.
From a standing position, after having just pressed on gas, there is an initial loss of power/pressure where I need to ease up on the gas pedal for a second. Driving misfires doen't seem to be as bad the rough idle. I have seen a code that indicated misfire on cylinder 6, but it is now random multiple.

I also had a no heat issue that was fixed by a replacing the coolant thermometer. But I do still notice a smell upon startup that smells a bit like fuel (as well as minor sweetish notes which to me should be coolant and perhaps a heater core issue). Would the misfires give me the fuel smell like this?

I imagine this is doing wonders for the catalytic converter.

My plan was to intially start with a replacement of the spark plugs & wires, distributor cap, rotor, and the perhaps a O2 sensor (rear?) since I think the diagnostic plan for P0172 says look at misfires before the O2 sensor, but i think I just read that an O2 sensor could be causing misfires. Can someone comment on my plan of action.

Just for the record, I also have issues with 4wd buttons not working, airbag (the airbag is unplugged), rear speakers, vent cfm capacity, door hinge issues, driver side window motor, transmission is apparently on its way out according to multiple mechanics (but has made it for the past 7 years).

I do love my blazer though... any help for me?

 

That would be my recommendation for a starting point and then see what codes (if any) are still there.

 

P0172 - Fuel Trim System Rich Bank 1
P030x - Random/Multiple Cylinder Misfire Detected

I can find no reference to the other two codes in either of my two online references for your year.

Your plan sounds good for a starting place. Before replacing any O2 sensors, I would swap them side to side to see if the code changes, but looking at the codes you have, it doesn't appear that you have an O2 sensor issue.

 

what about checking timing? is that a first step too or more down the line?

 

The timing is controlled by the PCM (computer), so unless you have removed the distributor for some reason, it's doubtful that it has changed.

 

I swapped the cap and rotor (ended up with DTC P0306) and went on to change the wires & plugs on 6,4, and 2 and had a huge problem with 2. It could not get #2 out with a straight extension, and using a universal joint, got it out, but had major trouble getting a new one in (almost 2-3 hours and 3 or 4 wasted plugs).

I think the shroud may have been in the way and was causing the plug to not line up properly. Attached is a picture of what I had in front of me.



The shock mount is in the way for a straight extension and the plug shroud may also have been in the way. Any one have any comments or suggestions? Did you also have to use a universal extension to get #2 out?

It seems strange since everyone is always concerned with #3.

 

When you added the plugs/wires did you still have those codes?

 

i didn't get to 1, 3, and 5 yet.

but i am still with p0300, but i am not getting P0172 System too Rich (Bank 1).

 

have you check your fuel pressure regulator? that is the most common thing to fail and cause problems

 

question?.....missfire victoms in the wheel wel is the rubber flap torn or missing a large piece? i have same trouble missfire and changed coil all the way 2 plugs stops shortly then after a wille missfire again. the flap in my wheel wels are both missing large sections and miss gets worse in rain....dry days its still there but not as bad....going through caps and rotors quickly. just a few thoughts